// 定义数组，对象
let obj = { name: '张三', age: 18 };

let arr1 = [1, 2, 3];

console.log(obj, arr1);

// 不能执行window,dom,bom
// alert(1);  //报错   alert is not defined
// document.getElementById('app'); // 报错  document is not defined
// console.log(abc);

while (true) {
    console.log(1);
}